835 lines
31 KiB
Python
Executable File
835 lines
31 KiB
Python
Executable File
#!/usr/bin/python3
|
|
|
|
# Creates DNS zone files for all of the domains of all of the mail users
|
|
# and mail aliases and restarts nsd.
|
|
########################################################################
|
|
|
|
import os, os.path, urllib.parse, datetime, re, hashlib, base64
|
|
import ipaddress
|
|
import rtyaml
|
|
import dns.resolver
|
|
|
|
from mailconfig import get_mail_domains
|
|
from utils import shell, load_env_vars_from_file, safe_domain_name, sort_domains
|
|
|
|
def get_dns_domains(env):
|
|
# Add all domain names in use by email users and mail aliases and ensure
|
|
# PRIMARY_HOSTNAME is in the list.
|
|
domains = set()
|
|
domains |= get_mail_domains(env)
|
|
domains.add(env['PRIMARY_HOSTNAME'])
|
|
return domains
|
|
|
|
def get_dns_zones(env):
|
|
# What domains should we create DNS zones for? Never create a zone for
|
|
# a domain & a subdomain of that domain.
|
|
domains = get_dns_domains(env)
|
|
|
|
# Exclude domains that are subdomains of other domains we know. Proceed
|
|
# by looking at shorter domains first.
|
|
zone_domains = set()
|
|
for domain in sorted(domains, key=lambda d : len(d)):
|
|
for d in zone_domains:
|
|
if domain.endswith("." + d):
|
|
# We found a parent domain already in the list.
|
|
break
|
|
else:
|
|
# 'break' did not occur: there is no parent domain.
|
|
zone_domains.add(domain)
|
|
|
|
# Make a nice and safe filename for each domain.
|
|
zonefiles = []
|
|
for domain in zone_domains:
|
|
zonefiles.append([domain, safe_domain_name(domain) + ".txt"])
|
|
|
|
# Sort the list so that the order is nice and so that nsd.conf has a
|
|
# stable order so we don't rewrite the file & restart the service
|
|
# meaninglessly.
|
|
zone_order = sort_domains([ zone[0] for zone in zonefiles ], env)
|
|
zonefiles.sort(key = lambda zone : zone_order.index(zone[0]) )
|
|
|
|
return zonefiles
|
|
|
|
def get_custom_dns_config(env):
|
|
try:
|
|
return rtyaml.load(open(os.path.join(env['STORAGE_ROOT'], 'dns/custom.yaml')))
|
|
except:
|
|
return { }
|
|
|
|
def write_custom_dns_config(config, env):
|
|
config_yaml = rtyaml.dump(config)
|
|
with open(os.path.join(env['STORAGE_ROOT'], 'dns/custom.yaml'), "w") as f:
|
|
f.write(config_yaml)
|
|
|
|
def do_dns_update(env, force=False):
|
|
# What domains (and their zone filenames) should we build?
|
|
domains = get_dns_domains(env)
|
|
zonefiles = get_dns_zones(env)
|
|
|
|
# Custom records to add to zones.
|
|
additional_records = get_custom_dns_config(env)
|
|
|
|
# Write zone files.
|
|
os.makedirs('/etc/nsd/zones', exist_ok=True)
|
|
updated_domains = []
|
|
for i, (domain, zonefile) in enumerate(zonefiles):
|
|
# Build the records to put in the zone.
|
|
records = build_zone(domain, domains, additional_records, env)
|
|
|
|
# See if the zone has changed, and if so update the serial number
|
|
# and write the zone file.
|
|
if not write_nsd_zone(domain, "/etc/nsd/zones/" + zonefile, records, env, force):
|
|
# Zone was not updated. There were no changes.
|
|
continue
|
|
|
|
# If this is a .justtesting.email domain, then post the update.
|
|
try:
|
|
justtestingdotemail(domain, records)
|
|
except:
|
|
# Hmm. Might be a network issue. If we stop now, will we end
|
|
# up in an inconsistent state? Let's just continue.
|
|
pass
|
|
|
|
# Mark that we just updated this domain.
|
|
updated_domains.append(domain)
|
|
|
|
# Sign the zone.
|
|
#
|
|
# Every time we sign the zone we get a new result, which means
|
|
# we can't sign a zone without bumping the zone's serial number.
|
|
# Thus we only sign a zone if write_nsd_zone returned True
|
|
# indicating the zone changed, and thus it got a new serial number.
|
|
# write_nsd_zone is smart enough to check if a zone's signature
|
|
# is nearing expiration and if so it'll bump the serial number
|
|
# and return True so we get a chance to re-sign it.
|
|
sign_zone(domain, zonefile, env)
|
|
|
|
# Now that all zones are signed (some might not have changed and so didn't
|
|
# just get signed now, but were before) update the zone filename so nsd.conf
|
|
# uses the signed file.
|
|
for i in range(len(zonefiles)):
|
|
zonefiles[i][1] += ".signed"
|
|
|
|
# Write the main nsd.conf file.
|
|
if write_nsd_conf(zonefiles, additional_records, env):
|
|
# Make sure updated_domains contains *something* if we wrote an updated
|
|
# nsd.conf so that we know to restart nsd.
|
|
if len(updated_domains) == 0:
|
|
updated_domains.append("DNS configuration")
|
|
|
|
# Kick nsd if anything changed.
|
|
if len(updated_domains) > 0:
|
|
shell('check_call', ["/usr/sbin/service", "nsd", "restart"])
|
|
|
|
# Write the OpenDKIM configuration tables.
|
|
if write_opendkim_tables(zonefiles, env):
|
|
# Settings changed. Kick opendkim.
|
|
shell('check_call', ["/usr/sbin/service", "opendkim", "restart"])
|
|
if len(updated_domains) == 0:
|
|
# If this is the only thing that changed?
|
|
updated_domains.append("OpenDKIM configuration")
|
|
|
|
if len(updated_domains) == 0:
|
|
# if nothing was updated (except maybe OpenDKIM's files), don't show any output
|
|
return ""
|
|
else:
|
|
return "updated DNS: " + ",".join(updated_domains) + "\n"
|
|
|
|
########################################################################
|
|
|
|
def build_zone(domain, all_domains, additional_records, env, is_zone=True):
|
|
records = []
|
|
|
|
# For top-level zones, define the authoritative name servers.
|
|
#
|
|
# Normally we are our own nameservers. Some TLDs require two distinct IP addresses,
|
|
# so we allow the user to override the second nameserver definition so that
|
|
# secondary DNS can be set up elsewhere.
|
|
#
|
|
# 'False' in the tuple indicates these records would not be used if the zone
|
|
# is managed outside of the box.
|
|
if is_zone:
|
|
# Obligatory definition of ns1.PRIMARY_HOSTNAME.
|
|
records.append((None, "NS", "ns1.%s." % env["PRIMARY_HOSTNAME"], False))
|
|
|
|
# Define ns2.PRIMARY_HOSTNAME or whatever the user overrides.
|
|
secondary_ns = additional_records.get("_secondary_nameserver", "ns2." + env["PRIMARY_HOSTNAME"])
|
|
records.append((None, "NS", secondary_ns+'.', False))
|
|
|
|
|
|
# In PRIMARY_HOSTNAME...
|
|
if domain == env["PRIMARY_HOSTNAME"]:
|
|
# Define ns1 and ns2.
|
|
# 'False' in the tuple indicates these records would not be used if the zone
|
|
# is managed outside of the box.
|
|
records.append(("ns1", "A", env["PUBLIC_IP"], False))
|
|
records.append(("ns2", "A", env["PUBLIC_IP"], False))
|
|
if env.get('PUBLIC_IPV6'):
|
|
records.append(("ns1", "AAAA", env["PUBLIC_IPV6"], False))
|
|
records.append(("ns2", "AAAA", env["PUBLIC_IPV6"], False))
|
|
|
|
# Set the A/AAAA records. Do this early for the PRIMARY_HOSTNAME so that the user cannot override them
|
|
# and we can provide different explanatory text.
|
|
records.append((None, "A", env["PUBLIC_IP"], "Required. Sets the IP address of the box."))
|
|
if env.get("PUBLIC_IPV6"): records.append((None, "AAAA", env["PUBLIC_IPV6"], "Required. Sets the IPv6 address of the box."))
|
|
|
|
# Add a DANE TLSA record for SMTP.
|
|
records.append(("_25._tcp", "TLSA", build_tlsa_record(env), "Recommended when DNSSEC is enabled. Advertises to mail servers connecting to the box that mandatory encryption should be used."))
|
|
|
|
# Add a SSHFP records to help SSH key validation. One per available SSH key on this system.
|
|
for value in build_sshfp_records():
|
|
records.append((None, "SSHFP", value, "Optional. Provides an out-of-band method for verifying an SSH key before connecting. Use 'VerifyHostKeyDNS yes' (or 'VerifyHostKeyDNS ask') when connecting with ssh."))
|
|
|
|
# The MX record says where email for the domain should be delivered: Here!
|
|
records.append((None, "MX", "10 %s." % env["PRIMARY_HOSTNAME"], "Required. Specifies the hostname (and priority) of the machine that handles @%s mail." % domain))
|
|
|
|
# SPF record: Permit the box ('mx', see above) to send mail on behalf of
|
|
# the domain, and no one else.
|
|
records.append((None, "TXT", 'v=spf1 mx -all', "Recommended. Specifies that only the box is permitted to send @%s mail." % domain))
|
|
|
|
# Add DNS records for any subdomains of this domain. We should not have a zone for
|
|
# both a domain and one of its subdomains.
|
|
subdomains = [d for d in all_domains if d.endswith("." + domain)]
|
|
for subdomain in subdomains:
|
|
subdomain_qname = subdomain[0:-len("." + domain)]
|
|
subzone = build_zone(subdomain, [], additional_records, env, is_zone=False)
|
|
for child_qname, child_rtype, child_value, child_explanation in subzone:
|
|
if child_qname == None:
|
|
child_qname = subdomain_qname
|
|
else:
|
|
child_qname += "." + subdomain_qname
|
|
records.append((child_qname, child_rtype, child_value, child_explanation))
|
|
|
|
def has_rec(qname, rtype, prefix=None):
|
|
for rec in records:
|
|
if rec[0] == qname and rec[1] == rtype and (prefix is None or rec[2].startswith(prefix)):
|
|
return True
|
|
return False
|
|
|
|
# The user may set other records that don't conflict with our settings.
|
|
for qname, rtype, value in get_custom_records(domain, additional_records, env):
|
|
if has_rec(qname, rtype): continue
|
|
records.append((qname, rtype, value, "(Set by user.)"))
|
|
|
|
# Add defaults if not overridden by the user's custom settings (and not otherwise configured).
|
|
defaults = [
|
|
(None, "A", env["PUBLIC_IP"], "Required. May have a different value. Sets the IP address that %s resolves to for web hosting and other services besides mail. The A record must be present but its value does not affect mail delivery." % domain),
|
|
("www", "A", env["PUBLIC_IP"], "Optional. Sets the IP address that www.%s resolves to, e.g. for web hosting." % domain),
|
|
(None, "AAAA", env.get('PUBLIC_IPV6'), "Optional. Sets the IPv6 address that %s resolves to, e.g. for web hosting. (It is not necessary for receiving mail on this domain.)" % domain),
|
|
("www", "AAAA", env.get('PUBLIC_IPV6'), "Optional. Sets the IPv6 address that www.%s resolves to, e.g. for web hosting." % domain),
|
|
]
|
|
for qname, rtype, value, explanation in defaults:
|
|
if value is None or value.strip() == "": continue # skip IPV6 if not set
|
|
if not is_zone and qname == "www": continue # don't create any default 'www' subdomains on what are themselves subdomains
|
|
if not has_rec(qname, rtype):
|
|
records.append((qname, rtype, value, explanation))
|
|
|
|
# Append the DKIM TXT record to the zone as generated by OpenDKIM.
|
|
opendkim_record_file = os.path.join(env['STORAGE_ROOT'], 'mail/dkim/mail.txt')
|
|
with open(opendkim_record_file) as orf:
|
|
m = re.match(r'(\S+)\s+IN\s+TXT\s+\( "([^"]+)"\s+"([^"]+)"\s*\)', orf.read(), re.S)
|
|
val = m.group(2) + m.group(3)
|
|
records.append((m.group(1), "TXT", val, "Recommended. Provides a way for recipients to verify that this machine sent @%s mail." % domain))
|
|
|
|
# Append a DMARC record.
|
|
records.append(("_dmarc", "TXT", 'v=DMARC1; p=quarantine', "Optional. Specifies that mail that does not originate from the box but claims to be from @%s is suspect and should be quarantined by the recipient's mail system." % domain))
|
|
|
|
# For any subdomain with an A record but no SPF or DMARC record, add strict policy records.
|
|
all_resolvable_qnames = set(r[0] for r in records if r[1] in ("A", "AAAA"))
|
|
for qname in all_resolvable_qnames:
|
|
if not has_rec(qname, "TXT", prefix="v=spf1 "):
|
|
records.append((qname, "TXT", 'v=spf1 a mx -all', "Prevents unauthorized use of this domain name for outbound mail by requiring outbound mail to originate from the indicated host(s)."))
|
|
dmarc_qname = "_dmarc" + ("" if qname is None else "." + qname)
|
|
if not has_rec(dmarc_qname, "TXT", prefix="v=DMARC1; "):
|
|
records.append((dmarc_qname, "TXT", 'v=DMARC1; p=reject', "Prevents unauthorized use of this domain name for outbound mail by requiring a valid DKIM signature."))
|
|
|
|
|
|
# Sort the records. The None records *must* go first in the nsd zone file. Otherwise it doesn't matter.
|
|
records.sort(key = lambda rec : list(reversed(rec[0].split(".")) if rec[0] is not None else ""))
|
|
|
|
return records
|
|
|
|
########################################################################
|
|
|
|
def get_custom_records(domain, additional_records, env):
|
|
for qname, value in additional_records.items():
|
|
# Is this record for the domain or one of its subdomains?
|
|
if qname != domain and not qname.endswith("." + domain): continue
|
|
|
|
# Turn the fully qualified domain name in the YAML file into
|
|
# our short form (None => domain, or a relative QNAME).
|
|
if qname == domain:
|
|
qname = None
|
|
else:
|
|
qname = qname[0:len(qname)-len("." + domain)]
|
|
|
|
# Short form. Mapping a domain name to a string is short-hand
|
|
# for creating A records.
|
|
if isinstance(value, str):
|
|
values = [("A", value)]
|
|
if value == "local" and env.get("PUBLIC_IPV6"):
|
|
values.append( ("AAAA", value) )
|
|
|
|
# A mapping creates multiple records.
|
|
elif isinstance(value, dict):
|
|
values = value.items()
|
|
|
|
# No other type of data is allowed.
|
|
else:
|
|
raise ValueError()
|
|
|
|
for rtype, value2 in values:
|
|
# The "local" keyword on A/AAAA records are short-hand for our own IP.
|
|
# This also flags for web configuration that the user wants a website here.
|
|
if rtype == "A" and value2 == "local":
|
|
value2 = env["PUBLIC_IP"]
|
|
if rtype == "AAAA" and value2 == "local":
|
|
if "PUBLIC_IPV6" not in env: continue # no IPv6 address is available so don't set anything
|
|
value2 = env["PUBLIC_IPV6"]
|
|
yield (qname, rtype, value2)
|
|
|
|
########################################################################
|
|
|
|
def build_tlsa_record(env):
|
|
# A DANE TLSA record in DNS specifies that connections on a port
|
|
# must use TLS and the certificate must match a particular certificate.
|
|
#
|
|
# Thanks to http://blog.huque.com/2012/10/dnssec-and-certificates.html
|
|
# for explaining all of this!
|
|
|
|
# Get the hex SHA256 of the DER-encoded server certificate:
|
|
certder = shell("check_output", [
|
|
"/usr/bin/openssl",
|
|
"x509",
|
|
"-in", os.path.join(env["STORAGE_ROOT"], "ssl", "ssl_certificate.pem"),
|
|
"-outform", "DER"
|
|
],
|
|
return_bytes=True)
|
|
certhash = hashlib.sha256(certder).hexdigest()
|
|
|
|
# Specify the TLSA parameters:
|
|
# 3: This is the certificate that the client should trust. No CA is needed.
|
|
# 0: The whole certificate is matched.
|
|
# 1: The certificate is SHA256'd here.
|
|
return "3 0 1 " + certhash
|
|
|
|
def build_sshfp_records():
|
|
# The SSHFP record is a way for us to embed this server's SSH public
|
|
# key fingerprint into the DNS so that remote hosts have an out-of-band
|
|
# method to confirm the fingerprint. See RFC 4255 and RFC 6594. This
|
|
# depends on DNSSEC.
|
|
#
|
|
# On the client side, set SSH's VerifyHostKeyDNS option to 'ask' to
|
|
# include this info in the key verification prompt or 'yes' to trust
|
|
# the SSHFP record.
|
|
#
|
|
# See https://github.com/xelerance/sshfp for inspiriation.
|
|
|
|
algorithm_number = {
|
|
"ssh-rsa": 1,
|
|
"ssh-dss": 2,
|
|
"ecdsa-sha2-nistp256": 3,
|
|
}
|
|
|
|
# Get our local fingerprints by running ssh-keyscan. The output looks
|
|
# like the known_hosts file: hostname, keytype, fingerprint. The order
|
|
# of the output is arbitrary, so sort it to prevent spurrious updates
|
|
# to the zone file (that trigger bumping the serial number).
|
|
keys = shell("check_output", ["ssh-keyscan", "localhost"])
|
|
for key in sorted(keys.split("\n")):
|
|
if key.strip() == "" or key[0] == "#": continue
|
|
try:
|
|
host, keytype, pubkey = key.split(" ")
|
|
yield "%d %d ( %s )" % (
|
|
algorithm_number[keytype],
|
|
2, # specifies we are using SHA-256 on next line
|
|
hashlib.sha256(base64.b64decode(pubkey)).hexdigest().upper(),
|
|
)
|
|
except:
|
|
# Lots of things can go wrong. Don't let it disturb the DNS
|
|
# zone.
|
|
pass
|
|
|
|
########################################################################
|
|
|
|
def write_nsd_zone(domain, zonefile, records, env, force):
|
|
# On the $ORIGIN line, there's typically a ';' comment at the end explaining
|
|
# what the $ORIGIN line does. Any further data after the domain confuses
|
|
# ldns-signzone, however. It used to say '; default zone domain'.
|
|
|
|
# The SOA contact address for all of the domains on this system is hostmaster
|
|
# @ the PRIMARY_HOSTNAME. Hopefully that's legit.
|
|
|
|
# For the refresh through TTL fields, a good reference is:
|
|
# http://www.peerwisdom.org/2013/05/15/dns-understanding-the-soa-record/
|
|
|
|
|
|
zone = """
|
|
$ORIGIN {domain}.
|
|
$TTL 1800 ; default time to live
|
|
|
|
@ IN SOA ns1.{primary_domain}. hostmaster.{primary_domain}. (
|
|
__SERIAL__ ; serial number
|
|
7200 ; Refresh (secondary nameserver update interval)
|
|
1800 ; Retry (when refresh fails, how often to try again)
|
|
1209600 ; Expire (when refresh fails, how long secondary nameserver will keep records around anyway)
|
|
1800 ; Negative TTL (how long negative responses are cached)
|
|
)
|
|
"""
|
|
|
|
# Replace replacement strings.
|
|
zone = zone.format(domain=domain, primary_domain=env["PRIMARY_HOSTNAME"])
|
|
|
|
# Add records.
|
|
for subdomain, querytype, value, explanation in records:
|
|
if subdomain:
|
|
zone += subdomain
|
|
zone += "\tIN\t" + querytype + "\t"
|
|
if querytype == "TXT":
|
|
value = value.replace('\\', '\\\\') # escape backslashes
|
|
value = value.replace('"', '\\"') # escape quotes
|
|
value = '"' + value + '"' # wrap in quotes
|
|
zone += value + "\n"
|
|
|
|
# DNSSEC requires re-signing a zone periodically. That requires
|
|
# bumping the serial number even if no other records have changed.
|
|
# We don't see the DNSSEC records yet, so we have to figure out
|
|
# if a re-signing is necessary so we can prematurely bump the
|
|
# serial number.
|
|
force_bump = False
|
|
if not os.path.exists(zonefile + ".signed"):
|
|
# No signed file yet. Shouldn't normally happen unless a box
|
|
# is going from not using DNSSEC to using DNSSEC.
|
|
force_bump = True
|
|
else:
|
|
# We've signed the domain. Check if we are close to the expiration
|
|
# time of the signature. If so, we'll force a bump of the serial
|
|
# number so we can re-sign it.
|
|
with open(zonefile + ".signed") as f:
|
|
signed_zone = f.read()
|
|
expiration_times = re.findall(r"\sRRSIG\s+SOA\s+\d+\s+\d+\s\d+\s+(\d{14})", signed_zone)
|
|
if len(expiration_times) == 0:
|
|
# weird
|
|
force_bump = True
|
|
else:
|
|
# All of the times should be the same, but if not choose the soonest.
|
|
expiration_time = min(expiration_times)
|
|
expiration_time = datetime.datetime.strptime(expiration_time, "%Y%m%d%H%M%S")
|
|
if expiration_time - datetime.datetime.now() < datetime.timedelta(days=3):
|
|
# We're within three days of the expiration, so bump serial & resign.
|
|
force_bump = True
|
|
|
|
# Set the serial number.
|
|
serial = datetime.datetime.now().strftime("%Y%m%d00")
|
|
if os.path.exists(zonefile):
|
|
# If the zone already exists, is different, and has a later serial number,
|
|
# increment the number.
|
|
with open(zonefile) as f:
|
|
existing_zone = f.read()
|
|
m = re.search(r"(\d+)\s*;\s*serial number", existing_zone)
|
|
if m:
|
|
# Clear out the serial number in the existing zone file for the
|
|
# purposes of seeing if anything *else* in the zone has changed.
|
|
existing_serial = m.group(1)
|
|
existing_zone = existing_zone.replace(m.group(0), "__SERIAL__ ; serial number")
|
|
|
|
# If the existing zone is the same as the new zone (modulo the serial number),
|
|
# there is no need to update the file. Unless we're forcing a bump.
|
|
if zone == existing_zone and not force_bump and not force:
|
|
return False
|
|
|
|
# If the existing serial is not less than a serial number
|
|
# based on the current date plus 00, increment it. Otherwise,
|
|
# the serial number is less than our desired new serial number
|
|
# so we'll use the desired new number.
|
|
if existing_serial >= serial:
|
|
serial = str(int(existing_serial) + 1)
|
|
|
|
zone = zone.replace("__SERIAL__", serial)
|
|
|
|
# Write the zone file.
|
|
with open(zonefile, "w") as f:
|
|
f.write(zone)
|
|
|
|
return True # file is updated
|
|
|
|
########################################################################
|
|
|
|
def write_nsd_conf(zonefiles, additional_records, env):
|
|
# Basic header.
|
|
nsdconf = """
|
|
server:
|
|
hide-version: yes
|
|
|
|
# identify the server (CH TXT ID.SERVER entry).
|
|
identity: ""
|
|
|
|
# The directory for zonefile: files.
|
|
zonesdir: "/etc/nsd/zones"
|
|
"""
|
|
|
|
# Since we have bind9 listening on localhost for locally-generated
|
|
# DNS queries that require a recursive nameserver, and the system
|
|
# might have other network interfaces for e.g. tunnelling, we have
|
|
# to be specific about the network interfaces that nsd binds to.
|
|
for ipaddr in (env.get("PRIVATE_IP", "") + " " + env.get("PRIVATE_IPV6", "")).split(" "):
|
|
if ipaddr == "": continue
|
|
nsdconf += " ip-address: %s\n" % ipaddr
|
|
|
|
# Append the zones.
|
|
for domain, zonefile in zonefiles:
|
|
nsdconf += """
|
|
zone:
|
|
name: %s
|
|
zonefile: %s
|
|
""" % (domain, zonefile)
|
|
|
|
# If a custom secondary nameserver has been set, allow zone transfers
|
|
# and notifies to that nameserver.
|
|
if additional_records.get("_secondary_nameserver"):
|
|
# Get the IP address of the nameserver by resolving it.
|
|
hostname = additional_records.get("_secondary_nameserver")
|
|
resolver = dns.resolver.get_default_resolver()
|
|
response = dns.resolver.query(hostname+'.', "A")
|
|
ipaddr = str(response[0])
|
|
nsdconf += """\tnotify: %s NOKEY
|
|
provide-xfr: %s NOKEY
|
|
""" % (ipaddr, ipaddr)
|
|
|
|
|
|
# Check if the nsd.conf is changing. If it isn't changing,
|
|
# return False to flag that no change was made.
|
|
with open("/etc/nsd/nsd.conf") as f:
|
|
if f.read() == nsdconf:
|
|
return False
|
|
|
|
with open("/etc/nsd/nsd.conf", "w") as f:
|
|
f.write(nsdconf)
|
|
|
|
return True
|
|
|
|
########################################################################
|
|
|
|
def dnssec_choose_algo(domain, env):
|
|
if domain.endswith(".email") or domain.endswith(".guide"):
|
|
# At least at GoDaddy, this is the only algorithm supported.
|
|
return "RSASHA256"
|
|
|
|
# For any domain we were able to sign before, don't change the algorithm
|
|
# on existing users. We'll probably want to migrate to SHA256 later.
|
|
return "RSASHA1-NSEC3-SHA1"
|
|
|
|
def sign_zone(domain, zonefile, env):
|
|
algo = dnssec_choose_algo(domain, env)
|
|
dnssec_keys = load_env_vars_from_file(os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/%s.conf' % algo))
|
|
|
|
# In order to use the same keys for all domains, we have to generate
|
|
# a new .key file with a DNSSEC record for the specific domain. We
|
|
# can reuse the same key, but it won't validate without a DNSSEC
|
|
# record specifically for the domain.
|
|
#
|
|
# Copy the .key and .private files to /tmp to patch them up.
|
|
#
|
|
# Use os.umask and open().write() to securely create a copy that only
|
|
# we (root) can read.
|
|
files_to_kill = []
|
|
for key in ("KSK", "ZSK"):
|
|
if dnssec_keys.get(key, "").strip() == "": raise Exception("DNSSEC is not properly set up.")
|
|
oldkeyfn = os.path.join(env['STORAGE_ROOT'], 'dns/dnssec/' + dnssec_keys[key])
|
|
newkeyfn = '/tmp/' + dnssec_keys[key].replace("_domain_", domain)
|
|
dnssec_keys[key] = newkeyfn
|
|
for ext in (".private", ".key"):
|
|
if not os.path.exists(oldkeyfn + ext): raise Exception("DNSSEC is not properly set up.")
|
|
with open(oldkeyfn + ext, "r") as fr:
|
|
keydata = fr.read()
|
|
keydata = keydata.replace("_domain_", domain) # trick ldns-signkey into letting our generic key be used by this zone
|
|
fn = newkeyfn + ext
|
|
prev_umask = os.umask(0o77) # ensure written file is not world-readable
|
|
try:
|
|
with open(fn, "w") as fw:
|
|
fw.write(keydata)
|
|
finally:
|
|
os.umask(prev_umask) # other files we write should be world-readable
|
|
files_to_kill.append(fn)
|
|
|
|
# Do the signing.
|
|
expiry_date = (datetime.datetime.now() + datetime.timedelta(days=30)).strftime("%Y%m%d")
|
|
shell('check_call', ["/usr/bin/ldns-signzone",
|
|
# expire the zone after 30 days
|
|
"-e", expiry_date,
|
|
|
|
# use NSEC3
|
|
"-n",
|
|
|
|
# zonefile to sign
|
|
"/etc/nsd/zones/" + zonefile,
|
|
|
|
# keys to sign with (order doesn't matter -- it'll figure it out)
|
|
dnssec_keys["KSK"],
|
|
dnssec_keys["ZSK"],
|
|
])
|
|
|
|
# Create a DS record based on the patched-up key files. The DS record is specific to the
|
|
# zone being signed, so we can't use the .ds files generated when we created the keys.
|
|
# The DS record points to the KSK only. Write this next to the zone file so we can
|
|
# get it later to give to the user with instructions on what to do with it.
|
|
#
|
|
# We want to be able to validate DS records too, but multiple forms may be valid depending
|
|
# on the digest type. So we'll write all (both) valid records. Only one DS record should
|
|
# actually be deployed. Preferebly the first.
|
|
with open("/etc/nsd/zones/" + zonefile + ".ds", "w") as f:
|
|
for digest_type in ('2', '1'):
|
|
rr_ds = shell('check_output', ["/usr/bin/ldns-key2ds",
|
|
"-n", # output to stdout
|
|
"-" + digest_type, # 1=SHA1, 2=SHA256
|
|
dnssec_keys["KSK"] + ".key"
|
|
])
|
|
f.write(rr_ds)
|
|
|
|
# Remove our temporary file.
|
|
for fn in files_to_kill:
|
|
os.unlink(fn)
|
|
|
|
########################################################################
|
|
|
|
def write_opendkim_tables(zonefiles, env):
|
|
# Append a record to OpenDKIM's KeyTable and SigningTable for each domain.
|
|
|
|
opendkim_key_file = os.path.join(env['STORAGE_ROOT'], 'mail/dkim/mail.private')
|
|
|
|
if not os.path.exists(opendkim_key_file):
|
|
# Looks like OpenDKIM is not installed.
|
|
return False
|
|
|
|
config = {
|
|
# The SigningTable maps email addresses to a key in the KeyTable that
|
|
# specifies signing information for matching email addresses. Here we
|
|
# map each domain to a same-named key.
|
|
#
|
|
# Elsewhere we set the DMARC policy for each domain such that mail claiming
|
|
# to be From: the domain must be signed with a DKIM key on the same domain.
|
|
# So we must have a separate KeyTable entry for each domain.
|
|
"SigningTable":
|
|
"".join(
|
|
"*@{domain} {domain}\n".format(domain=domain)
|
|
for domain, zonefile in zonefiles
|
|
),
|
|
|
|
# The KeyTable specifies the signing domain, the DKIM selector, and the
|
|
# path to the private key to use for signing some mail. Per DMARC, the
|
|
# signing domain must match the sender's From: domain.
|
|
"KeyTable":
|
|
"".join(
|
|
"{domain} {domain}:mail:{key_file}\n".format(domain=domain, key_file=opendkim_key_file)
|
|
for domain, zonefile in zonefiles
|
|
),
|
|
}
|
|
|
|
did_update = False
|
|
for filename, content in config.items():
|
|
# Don't write the file if it doesn't need an update.
|
|
if os.path.exists("/etc/opendkim/" + filename):
|
|
with open("/etc/opendkim/" + filename) as f:
|
|
if f.read() == content:
|
|
continue
|
|
|
|
# The contents needs to change.
|
|
with open("/etc/opendkim/" + filename, "w") as f:
|
|
f.write(content)
|
|
did_update = True
|
|
|
|
# Return whether the files changed. If they didn't change, there's
|
|
# no need to kick the opendkim process.
|
|
return did_update
|
|
|
|
########################################################################
|
|
|
|
def set_custom_dns_record(qname, rtype, value, env):
|
|
# validate qname
|
|
for zone, fn in get_dns_zones(env):
|
|
# It must match a zone apex or be a subdomain of a zone
|
|
# that we are otherwise hosting.
|
|
if qname == zone or qname.endswith("."+zone):
|
|
break
|
|
else:
|
|
# No match.
|
|
raise ValueError("%s is not a domain name or a subdomain of a domain name managed by this box." % qname)
|
|
|
|
# validate rtype
|
|
rtype = rtype.upper()
|
|
if value is not None:
|
|
if rtype in ("A", "AAAA"):
|
|
v = ipaddress.ip_address(value)
|
|
if rtype == "A" and not isinstance(v, ipaddress.IPv4Address): raise ValueError("That's an IPv6 address.")
|
|
if rtype == "AAAA" and not isinstance(v, ipaddress.IPv6Address): raise ValueError("That's an IPv4 address.")
|
|
elif rtype in ("CNAME", "TXT"):
|
|
# anything goes
|
|
pass
|
|
else:
|
|
raise ValueError("Unknown record type '%s'." % rtype)
|
|
|
|
# load existing config
|
|
config = get_custom_dns_config(env)
|
|
|
|
# update
|
|
if qname not in config:
|
|
if value is None:
|
|
# Is asking to delete a record that does not exist.
|
|
return False
|
|
elif rtype == "A":
|
|
# Add this record using the short form 'qname: value'.
|
|
config[qname] = value
|
|
else:
|
|
# Add this record. This is the qname's first record.
|
|
config[qname] = { rtype: value }
|
|
else:
|
|
if isinstance(config[qname], str):
|
|
# This is a short-form 'qname: value' implicit-A record.
|
|
if value is None and rtype != "A":
|
|
# Is asking to delete a record that doesn't exist.
|
|
return False
|
|
elif value is None and rtype == "A":
|
|
# Delete record.
|
|
del config[qname]
|
|
elif rtype == "A":
|
|
# Update, keeping short form.
|
|
if config[qname] == "value":
|
|
# No change.
|
|
return False
|
|
config[qname] = value
|
|
else:
|
|
# Expand short form so we can add a new record type.
|
|
config[qname] = { "A": config[qname], rtype: value }
|
|
else:
|
|
# This is the qname: { ... } (dict) format.
|
|
if value is None:
|
|
if rtype not in config[qname]:
|
|
# Is asking to delete a record that doesn't exist.
|
|
return False
|
|
else:
|
|
# Delete the record. If it's the last record, delete the domain.
|
|
del config[qname][rtype]
|
|
if len(config[qname]) == 0:
|
|
del config[qname]
|
|
else:
|
|
# Update the record.
|
|
if config[qname].get(rtype) == "value":
|
|
# No change.
|
|
return False
|
|
config[qname][rtype] = value
|
|
|
|
# serialize & save
|
|
write_custom_dns_config(config, env)
|
|
|
|
return True
|
|
|
|
########################################################################
|
|
|
|
def set_secondary_dns(hostname, env):
|
|
config = get_custom_dns_config(env)
|
|
|
|
if hostname in (None, ""):
|
|
# Clear.
|
|
if "_secondary_nameserver" in config:
|
|
del config["_secondary_nameserver"]
|
|
else:
|
|
# Validate.
|
|
hostname = hostname.strip().lower()
|
|
resolver = dns.resolver.get_default_resolver()
|
|
try:
|
|
response = dns.resolver.query(hostname, "A")
|
|
except (dns.resolver.NoNameservers, dns.resolver.NXDOMAIN, dns.resolver.NoAnswer):
|
|
raise ValueError("Could not resolve the IP address of %s." % hostname)
|
|
|
|
# Set.
|
|
config["_secondary_nameserver"] = hostname
|
|
|
|
# Save and apply.
|
|
write_custom_dns_config(config, env)
|
|
return do_dns_update(env)
|
|
|
|
|
|
########################################################################
|
|
|
|
def justtestingdotemail(domain, records):
|
|
# If the domain is a subdomain of justtesting.email, which we own,
|
|
# automatically populate the zone where it is set up on dns4e.com.
|
|
# Ideally if dns4e.com supported NS records we would just have it
|
|
# delegate DNS to us, but instead we will populate the whole zone.
|
|
|
|
import subprocess, json, urllib.parse
|
|
|
|
if not domain.endswith(".justtesting.email"):
|
|
return
|
|
|
|
for subdomain, querytype, value, explanation in records:
|
|
if querytype in ("NS",): continue
|
|
if subdomain in ("www", "ns1", "ns2"): continue # don't do unnecessary things
|
|
|
|
if subdomain == None:
|
|
subdomain = domain
|
|
else:
|
|
subdomain = subdomain + "." + domain
|
|
|
|
if querytype == "TXT":
|
|
# nsd requires parentheses around txt records with multiple parts,
|
|
# but DNS4E requires there be no parentheses; also it goes into
|
|
# nsd with a newline and a tab, which we replace with a space here
|
|
value = re.sub("^\s*\(\s*([\w\W]*)\)", r"\1", value)
|
|
value = re.sub("\s+", " ", value)
|
|
else:
|
|
continue
|
|
|
|
print("Updating DNS for %s/%s..." % (subdomain, querytype))
|
|
resp = json.loads(subprocess.check_output([
|
|
"curl",
|
|
"-s",
|
|
"https://api.dns4e.com/v7/%s/%s" % (urllib.parse.quote(subdomain), querytype.lower()),
|
|
"--user", "2ddbd8e88ed1495fa0ec:A97TDJV26CVUJS6hqAs0CKnhj4HvjTM7MwAAg8xb",
|
|
"--data", "record=%s" % urllib.parse.quote(value),
|
|
]).decode("utf8"))
|
|
print("\t...", resp.get("message", "?"))
|
|
|
|
########################################################################
|
|
|
|
def build_recommended_dns(env):
|
|
ret = []
|
|
domains = get_dns_domains(env)
|
|
zonefiles = get_dns_zones(env)
|
|
additional_records = get_custom_dns_config(env)
|
|
for domain, zonefile in zonefiles:
|
|
records = build_zone(domain, domains, additional_records, env)
|
|
|
|
# remove records that we don't dislay
|
|
records = [r for r in records if r[3] is not False]
|
|
|
|
# put Required at the top, then Recommended, then everythiing else
|
|
records.sort(key = lambda r : 0 if r[3].startswith("Required.") else (1 if r[3].startswith("Recommended.") else 2))
|
|
|
|
# expand qnames
|
|
for i in range(len(records)):
|
|
if records[i][0] == None:
|
|
qname = domain
|
|
else:
|
|
qname = records[i][0] + "." + domain
|
|
|
|
records[i] = {
|
|
"qname": qname,
|
|
"rtype": records[i][1],
|
|
"value": records[i][2],
|
|
"explanation": records[i][3],
|
|
}
|
|
|
|
# return
|
|
ret.append((domain, records))
|
|
return ret
|
|
|
|
if __name__ == "__main__":
|
|
from utils import load_environment
|
|
env = load_environment()
|
|
for zone, records in build_recommended_dns(env):
|
|
for record in records:
|
|
print("; " + record['explanation'])
|
|
print(record['qname'], record['rtype'], record['value'], sep="\t")
|
|
print()
|